Search results
Results from the WOW.Com Content Network
Generally polymers are unsaturated compounds like alkenes, alkalines etc. The addition polymerization mainly takes place in free radical mechanism. The free radical mechanism of addition polymerization completed by three steps i.e. Initiation of free radical, Chain propagation, Termination of chain.
Separately, unsubsituted compounds with a relative stable radical can dissociate from hydrogen. In general, these reactions risk polymerized byproducts (see § Side reactions). For example, in the thiol-ene reaction, thiols, [5]: 165–166 disulfides, [5]: 207 and hydrogen sulfide [5]: 191 add across a double bond. But if the unsaturated ...
An addition reaction is limited to chemical compounds that have multiple bonds. Examples include a molecule with a carbon–carbon double bond (an alkene ) or a triple bond (an alkyne ). Another example is a compound that has rings (which are also considered points of unsaturation ).
Polyaddition (or addition polymerisation [2] [3]) is a polymerization reaction that forms polymers via individual independent addition reactions.Polyaddition occurs as a reaction between functional groups on molecules with low degrees of polymerization, such as dimers, trimers and oligomers, to form species of higher molar mass.
In this reaction a variety of reagents add "across" the pi-bond(s). Chlorine, hydrogen chloride, water, and hydrogen are illustrative reagents. Polymerization is a form of addition. Alkenes and some alkynes also undergo polymerization by opening of the multiple bonds to produce polyethylene, polybutylene, and polystyrene.
Reversible Addition-Fragmentation Chain-Transfer Polymerization (RAFT): requires a compound that can act as a reversible chain-transfer agent, such as dithio compound. [2] Stable Free Radical Polymerization (SFRP): used to synthesize linear or branched polymers with narrow molecular weight distributions and reactive end groups on each polymer ...
In these cases, the alkenes RCH=CH 2 are converted to high molecular weight alkanes (-RCHCH 2-) n (R = H, CH 3, Cl, CO 2 CH 3). Other forms of chain growth polymerization include cationic addition polymerization and anionic addition polymerization. A special case of chain-growth polymerization leads to living polymerization.
The rule states that with the addition of a protic acid HX or other polar reagent to an asymmetric alkene, the acid hydrogen (H) or electropositive part gets attached to the carbon with more hydrogen substituents, and the halide (X) group or electronegative part gets attached to the carbon with more alkyl substituents. This is in contrast to ...